1. Field of the Invention
The invention generally relates to mobile capability signaling, and more particularly, to apparatuses and methods for reporting mobile capability concerning the features of carrier aggregation.
2. Description of the Related Art
In a typical mobile communications environment, a user equipment (UE), including a mobile telephone (also known as a cellular or cell phone), a laptop computer with wireless communications capability, or a personal digital assistant (PDA) etc., may communicate voice and/or data signals with one or more service network. The wireless communications between the UE and the service networks may be in compliance with various wireless technologies, such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced technology, and others. Take the LTE technology in compliance with the 3GPP TS 36.331 specification (referred to herein as the TS 36.331 specification) as an example. A UE supports only a single carrier transmission and reception, and the capability of the UE is signaled to the network side by a “ue-Category” parameter which contains 5 categories standing for 5 different sets of combined downlink/uplink data rates, Hybrid Automatic Repeat reQuest (HARQ) processing capability, and multi-antenna capability, etc.
In order to meet users' demand for higher data rate in wireless communications, support of wider transmission bandwidths is required and the so-called Carrier Aggregation (CA) technique has been proposed to allow expansion of effective bandwidths delivered to a UE through concurrent utilization of radio resources across multiple carriers. The CA technique is most useful when it is difficult to derive a contiguous and extra wide bandwidth. With the CA technique, more than 2 frequency bands may be aggregated to form a larger transmission/receive bandwidth. Each of the aggregated frequency channels is generally referred to as a Component Carrier (CC), which may be taken as a component of the aggregated bandwidth. With the advancement from single-carrier transceiving to multiple-carrier transceiving, the conventional way of mobile capability signaling for single-carrier capability is no longer adequate. Thus, it is desirable to provide a new way of mobile capability signaling for a UE to report its carrier aggregation capability.